Below a certain income it is pretty safe to assume virtually all money is spent, so adding in sales/VAT taxes seems reasonable.
tyrant, 100 grand in Canada puts them in the top 5%—RICH, not middle class (caveat: the canadian stats page I found said that 89 grand put you in the top 5%, but the data was 2004).
That's the trick. Pols say "tax the rich!" and the people hearing it think, "yeah, tax those rich bastards, not the middle class like me!" They don't realize THEY are rich to the pols.